Police said the victim ran through the neighborhood and pounded on a neighbor's door for help.
"He was running up banging on windows, going house to house trying to look for help because he was already shot," said witness Cindy Gomez.
The 50-year-old victim was declared dead on the front porch of the home. His identity has not yet been released pending notification of next of kin.
The neighborhood was locked down overnight as police searched for the killer. Investigators spent hours carefully searching for bullet casings and clues while nervous neighbors looked on.
"They didn't even let us walk on our grass, not even going to the sidewalk," said resident Vianey Amador.
Resident Louise Marchello was shocked to learn of the shooting and quick to defend her neighborhood as a safe area where neighbors help each other.
"You never hear any arguing, fighting, or anything. It's just a nice neighborhood. If you ever need something we're there for you," said Marchello.
"This is the first time that this happens right here. This is a quiet area and it's so strange and it's kind of shocking because I've never seen something like this right here," said Amador.
Police have not released a motive for the shooting. Anyone with information was urged to call the Pomona Police Department at (909) 622-1241.